Multi-Function Exhaust System for Diesel and Natural Gas Engines

ABSTRACT

A multi-functional exhaust system for diesel and natural gas engines includes a rectangular box housing, a selective catalytic reduction (SCR) unit, at least one reductant injector, a plurality of sensors, and a mixing duct to mix the injected reductant and the exhaust gas. A portion of the mixing duct runs in parallel beside the SCR unit reducing the overall length of the housing. Another portion of the mixing duct routes the exhaust gas through a 180 degree bend to redirect the exhaust gas to the SCR unit. The SCR unit and mixing duct are positioned within the housing and in fluid communication with an inlet and an outlet of the housing. The inlet is in fluid communication with an engine, and the outlet is in fluid communication with an exhaust outlet so that the housing can be secured as the exhaust system.

FIELD OF THE INVENTION

The present disclosure relates to exhaust gas after-treatment systems for diesel and natural gas engines. More specifically, the present invention consists of a single rectangular box housing which contains a selective catalytic reduction unit and a mixing duct. The mixing duct is partially beside the selective catalytic reduction unit as opposed to being completely in front of the selective catalytic reduction unit. The positioning of the mixing duct reduces overall length of the rectangular box housing. Various other embodiments of the present invention allow the rectangular box housing to accommodate additional emission reduction devices thereby eliminating the interconnecting piping associated with those respective additional emission devices that might otherwise be required for those additional emission reduction functions.

BACKGROUND OF THE INVENTION

Exhaust gas after-treatment systems have become particularly important due to stringent regulatory air emission and exhaust silencing limits on diesel and natural gas engines. A selective catalytic reduction (SCR) unit, which is used to reduce NO_(x) of the exhaust gas, is one of the most space intensive components used in emissions reduction. This is partially because the mixing duct used to mix an injected reductant with the exhaust gas is located in front of the SCR unit. To reduce the space required for the SCR unit, the present invention places the mixing duct in the same rectangular box housing as the SCR unit and locates a portion of the mixing duct beside as opposed to being completely in front of the SCR unit. Additionally, various embodiments of this invention provide space within the rectangular box housing to place other emission reduction devices thereby saving further space by eliminating any interconnecting piping associated with those emission reduction devices.

A typical exhaust gas after-treatment system may comprise many different individual emission reduction functions. In addition to SCR units, examples of emission reduction devices include an oxidation catalyst unit, a particulate filter unit, and a muffler unit along with the required sensors. While the control of NO_(x) emissions is mainly done using the SCR unit, other harmful particles and elements are controlled through the oxidation catalyst unit and the particulate filter unit. The muffler unit normally provides the silencing aspect so that the exhaust sound emissions can be reduced before exiting the exhaust gas after-treatment system. In order to complete the traditional exhaust gas after-treatment system, all or any combination of the devices that perform the emission reduction functions are connected to each other through an inter-connecting piping system.

The present invention incorporates the SCR unit and the mixing duct within a single rectangular box housing. To save space, a portion of the mixing duct is located immediately beside the SCR unit as opposed to being completely in front of it. The single rectangular box housing, which contains the SCR unit and the mixing duct, can also be used to house all or any combination of the oxidation catalyst unit, the particulate filter unit and the muffler unit, thereby saving further space by eliminating the interconnecting piping that would be associated if each of the other emission reduction devices are positioned as separate devices. Since all of the emission reduction devices can be contained within the rectangular box housing, the present invention makes installation much easier compared to the individual systems. In addition, the present invention is able to withstand increased seismic or vibration issues because the present invention is more rigid than a system that implements exhaust silencing and/or emission devices in multiple systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention.

FIG. 2 is a perspective view of the first embodiment of the present invention, showing the rectangular box housing, the passageway, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 3 is a top view of the present invention that corresponds to the first embodiment shown in FIG. 2.

FIG. 4 is a perspective view of the first embodiment of the present invention, showing the rectangular box housing, the at least one muffler, the passageway, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 5 is a top view of the present invention that corresponds to the first embodiment shown in FIG. 4.

FIG. 6 is a perspective view of the second embodiment of the present invention, showing the rectangular box housing, the oxidation catalyst unit, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 7 is a top view of the present invention that corresponds to the second embodiment shown in FIG. 6.

FIG. 8 is a perspective view of the second embodiment of the present invention, showing the rectangular box housing, the oxidation catalyst unit, the at least one muffler, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 9 is a top view of the present invention that corresponds to the second embodiment shown in FIG. 8.

FIG. 10 is a perspective view of the third embodiment of the present invention, showing the rectangular box housing, the oxidation catalyst unit, the particulate filter unit, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 11 is a top view of the present invention that corresponds to the third embodiment shown in FIG. 10.

FIG. 12 is a perspective view of the third embodiment of the present invention, showing the rectangular box housing, the oxidation catalyst unit, the at least one muffler, the particulate filter unit, the mixing duct, the SCR unit, the at least one reductant injector, and the sensors.

FIG. 13 is a top view of the present invention that corresponds to the third embodiment shown in FIG. 12.

FIG. 14 is a basic illustration showing the electrical connections of the present invention.

DETAIL DESCRIPTIONS OF THE INVENTION

All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.

The present invention accommodates a multi-functional exhaust system for diesel and natural gas engines as the present invention forms a single exhaust apparatus that is capable of performing silencing and emission functionalities. The traditional exhaust system for diesel and natural gas engines comprises multiple filtering devices in order to properly clean the generated exhaust gas that exits from the engine. The generated exhaust gas generally travels through the multiple filtering devices and ultimately escapes into the atmosphere through an exhaust outlet as the multiple filtering devices are connected to each other through an interconnecting piping system. However, the present invention completely eliminates the interconnecting piping system while combining multiple filtering devices into the single exhaust apparatus. In reference to FIG. 1-2, the present invention comprises a rectangular box housing 1, a passageway 2, a mixing duct 3, a Selective Catalytic Reduction (SCR) unit 4, at least one Nitrogen Oxides (NO_(x)) sensor 5, at least one temperature sensor 6, at least one pressure sensor 7, and at least one reductant injector 8. The present invention is in fluid communication with the engine and the exhaust outlet that opens up to the atmosphere. More specifically, an inlet 11 of the rectangular box housing 1 is in fluid communication with the engine and an outlet 12 of the rectangular box housing 1 is in fluid communication with the exhaust outlet as the rectangular box housing 1 protects the SCR unit 4 from the outside elements and functions as a supporting structure for the passageway 2, the mixing duct 3, the SCR unit 4, the at least one NO_(x) sensor 5, the at least one temperature sensor 6, the at least one pressure sensor 7, and the at least one reductant injector 8.

In reference to FIG. 1, the inlet 11 is shown from the bottom of the rectangular box housing 1 representing a single embodiment of the present invention. In addition to traversing from the bottom of the rectangular box housing 1 as shown in FIG. 1, the inlet 11 can traverse into the rectangular box housing 1 from the top or any side of the rectangular box housing 1 as long as the inlet 11 is able to maintain the in fluid communication between the passageway 2 and the engine.

In reference to FIG. 1, the outlet 12 is shown from the top of the rectangular box housing 1 representing a single embodiment of the present invention. In addition to traversing from the top of the rectangular box housing 1 as shown in FIG. 1, the outlet 12 can traverse into the rectangular box housing 1 from the bottom or any side of the rectangular box housing 1 as long as the outlet 12 is able to maintain the in fluid communication between the SCR unit 4 and the exhaust outlet.

In reference to a first embodiment of the present invention that is shown in FIG. 2-5, the inlet 11 is traversed into the rectangular box housing 1 and positioned adjacent to the mixing duct 3 in such a way that the inlet 11 is in fluid communication with the mixing duct 3 through the passageway 2. The passageway 2 provides an opening in between the inlet 11 and the mixing duct 3 so that the generated exhaust gas can flow from the inlet 11 into the mixing duct 3.

In reference to FIG. 3 and FIG. 5, the mixing duct 3 provides the necessary space for the generated exhaust gas to mix with a reductant agent from the at least one reductant injector 8 and is in fluid communication with the SCR unit 4. More specifically, the mixing duct 3 comprises at least one mixing vane 33, an elongated portion 34, and a shortened portion 35. The elongated portion 34 is adjacently positioned with the passageway 2 and provides so that the generated exhaust gas from the inlet 11 is able to flow into the elongated portion 34. The shortened portion 35 is perpendicularly positioned with the elongated portion 34 opposite of the passageway 2 so that the generated exhaust gas has to bend 180 degrees to bring the generated exhaust to the SCR unit 4. In other words, the elongated portion 34 and the shortened portion 35 form an L-shaped mixing duct 3 as the elongated portion 34 is positioned beside the SCR unit 4 and the shortened portion 35 is directly positioned in front of the SCR unit 4. Since the elongated portion 34 is located beside the SCR unit 4, the mixing duct 3 is able to reduce the overall length of the rectangular box housing 1. In order to attain the proper chemical reaction in between the reductant agent and the generated exhaust gas, the at least one mixing vane 33 is internally connected to the mixing duct 3 so that the at least one mixing vane 33 can function as a turbulence generator for the generated exhaust gas. As a result, the reductant agent injected by the reductant injector 8 is uniformly mixed with the generated exhaust gas in the mixing duct 3 before flowing into the SCR unit 4.

The at least one reductant injector 8 supplies the reductant agent from a secondary tank. In reference to FIG. 3, FIG. 5, and FIG. 14, the at least one reductant injector 8 is traversed into the rectangular box housing 1 and in fluid communication with the mixing duct 3. More specifically, the at least one reductant injector 8 is in fluid communication with the mixing duct 3 and adjacently positioned in between the passageway 2 and the SCR unit 4. Even though the at least one reductant injector 8 supplies the reductant agent, the flow rate of the reductant agent is controlled through the emissions control unit 9 as the at least one reductant injector 8 is electrically connected with the emissions control unit 9. The emissions control unit 9 takes input data from the at least one NO_(x) sensor 5, the at least one temperature sensor 6, the at least one pressure sensor 7 and calculates using an algorithm the amount of reductant agent to be injected through the at least one reductant injector 8.

The SCR unit 4 functions as an emission controlling device as the SCR unit 4 transforms nitrogen oxides into diatomic nitrogen (N₂) and water vapor with the aid of a catalyst and the reductant agent. More specifically, the reductant agent that is added to the generated exhaust gas through reductant injector 8 goes through a chemical reaction so that the SCR unit 4 is able to convert the nitrogen oxides into N₂ and water vapor. The details of how the SCR unit 4 reduces nitrogen oxides emissions are known to those with ordinary skill in the art and are not discussed further herein. In reference to FIG. 2-5, the SCR unit 4 is positioned within the rectangular box housing 1 in such way that the SCR unit 4 is in fluid communication with the outlet 12.

The outlet 12 is traversed into the rectangular box housing 1 and positioned adjacent to the SCR unit 4 in such a way that the outlet 12 is in fluid communication with the mixing duct 3 through the SCR unit 4.

The at least one NO_(x) sensor 5 can detect the nitrogen oxides level in the generated exhaust gas. The at least one NO_(x) sensor 5 detects any form of nitrogen oxides and continuously communicates with an emissions control unit 9 so that the nitrogen oxides can be reduced by the SCR unit 4. In reference to FIG. 3, FIG. 5, and FIG. 14, the at least one NO_(x) sensor 5 is traversed into the rectangular box housing 1. More specifically, the at least one NO_(x) sensor 5 is traversed into the mixing duct 3 and positioned in between the passageway 2 and the SCR unit 4. Additionally, the at least one NO_(x) sensor 5 is electrically connected with the emissions control unit 9 so that the at least one NO_(x) sensor 5 is able to provide the input data for the emissions control unit 9.

The at least one temperature sensor 6 measures the temperature variations in the generated exhaust gas as the at least one temperature sensor 6 continuously communicates with the emission control unit 9. In reference to FIG. 3, FIG. 5, and FIG. 14, the at least one temperature sensor 6 is traversed into the rectangular box housing 1 in such a way that the at least one temperature sensor 6 is positioned in between the SCR unit 4 and the outlet 12. The at least one temperature sensor 6 is also electrically connected with the emissions control unit 9 so that the at least one temperature sensor 6 can perform according to the system specifications and provide input data to the emission control unit 9.

The at least one pressure sensor 7 measures the pressure variations in the generated exhaust gas as the at least one pressure sensor 7 continuously communicates with the emissions control unit 9. In reference to FIG. 3, FIG. 5, and FIG. 14, the at least one pressure sensor 7 is traversed into the rectangular box housing 1 in such a way that the at least one pressure sensor 7 is positioned in between the SCR unit 4 and the outlet 12. The at least one pressure sensor 7 is also electrically connected with the emissions control unit 9 so that the at least one pressure sensor 7 can perform according to the system specifications and provide input data to the emission control unit 9.

In reference to a second embodiment of the present invention that is shown in FIG. 6-9, the second embodiment is configured similar to the first embodiment with common components. However, the rectangular box housing 1 of the second embodiment further comprises an oxidation catalyst unit 31 to reduce carbon monoxide and unburned hydrocarbon emissions in the generated exhaust gas. The oxidation catalyst unit 31 is positioned within the rectangular box housing 1 in such a way that the oxidation catalyst unit 31 is in fluid communication with the SCR unit 4. As a result, the oxidation catalyst unit 31 is able to filter the generated exhaust gas before the generated exhaust gas is escaped into atmosphere through the outlet 12. The location of the oxidation catalyst unit 31 within the rectangular box housing 1 can vary depending on the amount of carbon monoxide and unburned hydrocarbon emissions reduction required. For example, the oxidation catalyst unit 31 can be positioned adjacent to the passageway 2 or can be positioned adjacent to the SCR unit 4. The details of how the oxidation catalyst unit 31 reduces carbon monoxide and unburned hydrocarbon emissions are known to those with ordinary skill in the art and are not discussed further herein.

In reference to a third embodiment of the present invention that is shown in FIG. 10-13, the third embodiment is configured similar to the first embodiment with common components. However, the rectangular box housing 1 of the third embodiment further comprises the oxidation catalyst unit 31 and a particulate filter unit 32. The oxidation catalyst unit 31 that reduces carbon monoxide and unburned hydrocarbon emissions in the generated exhaust gas is positioned within the rectangular box housing 1 and is in fluid communication with the SCR unit 4. The location of the oxidation catalyst unit 31 within the rectangular box housing 1 can vary depending on the amount of carbon monoxide and unburned hydrocarbon emissions reduction required. The details of how the oxidation catalyst unit 31 reduces carbon monoxide and unburned hydrocarbon emissions are known to those with ordinary skill in the art and are not discussed further herein. The particulate filter unit 32 that reduces inorganic particle emissions in the generated exhaust gas is positioned within the rectangular box housing 1 adjacent to the oxidation catalyst unit 31. The particulate filter unit 32 is in fluid communication with the oxidation catalyst unit 31 so that the oxidation catalyst unit 31 and the particulate filter unit 32 are able to filter the generated exhaust gas before the generated exhaust gas is escaped into atmosphere through the outlet 12. The location of the particulate filter unit 32 can vary depending on the amount of inorganic particle emissions reduction required. The details of how the particulate filter unit 32 reduces amount of inorganic particle emissions are known to those with ordinary skill in the art and are not discussed further herein.

The first embodiment, the second embodiment, and the third embodiment of the present invention can also be configured with at least one muffler unit 13 as the rectangular box housing 1 further comprises the at least one muffler unit 13. In reference to FIG. 4, FIG. 8, and FIG. 12, the at least one muffler unit 13 is positioned within the rectangular box housing 1 adjacent to the inlet 11 and the outlet 12 in such way that the at least one muffler unit 13 is in fluid communication with the inlet 11 and the outlet 12 respectively. The muffler unit 13 reduces the noise emissions created by the generated exhaust gas. The exact positioning of the at least one muffler unit 13 inside of the rectangular box housing 1 can vary depending on the amount of noise emissions reduction required. In other words, the at least one muffler unit 13 can be in fluid communication with either the inlet 11 or the outlet 12 within one configuration and can be in fluid communication with both the inlet 11 and the outlet 12 within another configuration. The details of how the at least one muffler unit 13 reduces noise emissions are known to those with ordinary skill in the art and are not discussed further herein.

Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. 

What is claimed is:
 1. A multi-functional exhaust system for diesel and natural gas engines comprises: a rectangular box housing; a passageway; a mixing duct; a selective catalytic reduction (SCR) unit; at least one nitrogen oxide (NO_(x)) sensor; at least one temperature sensor; at least one pressure sensor; at least one reductant injector; the rectangular box housing comprises an inlet and an outlet; the inlet being in fluid communication with the mixing duct through the passageway; the mixing duct being in fluid communication with the SCR unit, wherein the mixing duct mixes the exhaust gas and the reductant agent from the at least one reductant injector; the SCR unit being in fluid communication with the outlet; and the at least one NO_(x) sensor, the at least one temperature sensor, the at least one pressure sensor, and the at least one reductant injector traversing into the rectangular box housing.
 2. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the inlet traversing into the rectangular box housing; the inlet being adjacently positioned with the mixing duct; the outlet traversing into the rectangular box housing; and the outlet being adjacently positioned with the SCR unit.
 3. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the rectangular box housing further comprises at least one muffler unit; the at least one muffler unit being positioned within the rectangular box housing adjacent to the inlet; and the at least one muffler unit being in fluid communication with the inlet.
 4. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the rectangular box housing further comprises at least one muffler unit; the at least one muffler unit being positioned within the rectangular box housing adjacent to the outlet; and the at least one muffler unit being in fluid communication with the outlet.
 5. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the mixing duct comprises at least one mixing vane, an elongated portion and a shortened portion; the elongated portion being adjacently positioned with the passageway, wherein the generated exhaust gas flows through the elongated portion; the shortened portion being perpendicularly positioned with the elongated portion opposite of the passageway, wherein the shortened portion causes the generated exhaust gas to bend 180 degrees to bring the generated exhaust gas to the SCR unit; the shortened portion being adjacently positioned with the SCR unit; and the at least one mixing vane being internally connected to the mixing duct.
 6. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the rectangular box housing further comprises an oxidation catalyst unit; the oxidation catalyst unit being positioned within the rectangular box housing; and the oxidation catalyst unit being in fluid communication with the SCR unit.
 7. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the rectangular box housing further comprises an oxidation catalyst unit and a particulate filter unit; the oxidation catalyst unit being positioned within the rectangular box housing; the oxidation catalyst unit being in fluid communication with the SCR unit; the particulate filter unit being positioned within the rectangular box housing adjacent to the oxidation catalyst unit; and the particulate filter unit being in fluid communication with the oxidation catalyst unit.
 8. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the at least one NO_(x) sensor being traversed into the mixing duct; the at least one NO_(x) sensor being positioned in between the passageway and the SCR unit; and the at least one NO_(x) sensor being electrically connected with an emissions control unit.
 9. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the at least one temperature sensor being positioned in between the SCR unit and the outlet; and the at least one temperature sensor being electrically connected with an emissions control unit.
 10. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the at least one pressure sensor being positioned in between the SCR unit and the outlet; and the at least one pressure sensor being electrically connected with an emissions control unit.
 11. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 1 comprises; the at least one reductant injector being in fluid communication with the mixing duct, wherein the reductant injector provides the reducing agent from a secondary tank; and the at least one reductant injector being electrically connected with an emissions control unit.
 12. A multi-functional exhaust system for diesel and natural gas engines comprises: a rectangular box housing; a passageway; a mixing duct; a selective catalytic reduction (SCR) unit; at least one nitrogen oxide (NO_(x)) sensor; at least one temperature sensor; at least one pressure sensor; at least one reductant injector; the rectangular box housing comprises an inlet and an outlet; the inlet being in fluid communication with the mixing duct through the passageway; the mixing duct being in fluid communication with the SCR unit, wherein the mixing duct mixes the exhaust gas and the reductant agent from the at least one reductant injector; the SCR unit being in fluid communication with the outlet; the at least one NO_(x) sensor, the at least one temperature sensor, the at least one pressure sensor, and the at least one reductant injector traversing into the rectangular box housing; the at least one reductant injector being in fluid communication with the mixing duct, wherein the reductant injector provides the reducing agent from a secondary tank; and the at least one reductant injector being electrically connected with an emissions control unit.
 13. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the inlet traversing into the rectangular box housing; the inlet being adjacently positioned with the mixing duct; the outlet traversing into the rectangular box housing; and the outlet being adjacently positioned with the SCR unit.
 14. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the rectangular box housing further comprises at least one muffler unit; the at least one muffler unit being positioned within the rectangular box housing adjacent to the inlet; and the at least one muffler unit being in fluid communication with the inlet.
 15. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the rectangular box housing further comprises at least one muffler unit; the at least one muffler unit being positioned within the rectangular box housing adjacent to the outlet; and the at least one muffler unit being in fluid communication with the outlet.
 16. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the mixing duct comprises at least one mixing vane, an elongated portion and a shortened portion; the elongated portion being adjacently positioned with the passageway, wherein the generated exhaust gas flows through the elongated portion; the shortened portion being perpendicularly positioned with the elongated portion opposite of the passageway, wherein the shortened portion causes the generated exhaust gas to bend 180 degrees to bring the generated exhaust gas to the SCR unit; the shortened portion being adjacently positioned with the SCR unit; and the at least one mixing vane being internally connected to the mixing duct.
 17. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the rectangular box housing further comprises an oxidation catalyst unit; the oxidation catalyst unit being positioned within the rectangular box housing; and the oxidation catalyst unit being in fluid communication with the SCR unit.
 18. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the rectangular box housing further comprises an oxidation catalyst unit and a particulate filter unit; the oxidation catalyst unit being positioned within the rectangular box housing; the oxidation catalyst unit being in fluid communication with the SCR unit; the particulate filter unit being positioned within the rectangular box housing adjacent to the oxidation catalyst unit; and the particulate filter unit being in fluid communication with the oxidation catalyst unit.
 19. The multi-functional exhaust system for diesel and natural gas engines as claimed in claim 12 comprises; the at least one NO_(x) sensor being traversed into the mixing duct; the at least one NO_(x) sensor being positioned in between the passageway and the SCR unit; the at least one NO_(x) sensor being electrically connected with the emissions control unit; the at least one temperature sensor being positioned in between the SCR unit and the outlet; the at least one temperature sensor being electrically connected with the emissions control unit; the at least one pressure sensor being positioned in between the SCR unit and the outlet; and the at least one pressure sensor being electrically connected with the emissions control unit. 